Again, the + symbol isn't a command and does nothing. If you searched for [libmad +tutorial] we saw that as as search for pages with both or either of two words

Again, the + symbol isn't a command and does nothing. If you searched for [libmad +tutorial] we saw that as as search for pages with both or either of two words, libmad OR +tutorial, plus any related words or synonyms, like tutorial. So with that search, we're trying to show you things we think are relevant, and there aren't a lot of pages relevant with the word +tutorial on them. Tutorial, yes -- but not +tutorial. In this case, what you really want is this: [libmad "tutorial"] -- that says get pages that have both words or words related to libmad but ONLY pages that actually have the word tutorial on them.